diff --git a/container/blockchain.go b/container/blockchain.go
index 434a4a91..26e7519a 100644
--- a/container/blockchain.go
+++ b/container/blockchain.go
@@ -44,6 +44,10 @@ const (
 	defaultPassword  = ""
 )
 
+type NodeIncubator interface {
+	CreateNodes(int, ...Option) ([]Ethereum, error)
+}
+
 type Blockchain interface {
 	AddValidators(numOfValidators int) ([]Ethereum, error)
 	RemoveValidators(candidates []Ethereum, t time.Duration) error
@@ -52,7 +56,6 @@ type Blockchain interface {
 	Stop(bool) error
 	Validators() []Ethereum
 	Finalize()
-	CreateNodes(int, ...Option) ([]Ethereum, error)
 }
 
 func NewBlockchain(network *DockerNetwork, numOfValidators int, options ...Option) (bc *blockchain) {
diff --git a/tests/functional/block_sync_test.go b/tests/functional/block_sync_test.go
index 17065ea9..4e1c7f72 100644
--- a/tests/functional/block_sync_test.go
+++ b/tests/functional/block_sync_test.go
@@ -52,7 +52,11 @@ var _ = Describe("Block synchronization testing", func() {
 
 		BeforeEach(func() {
 			var err error
-			nodes, err = blockchain.CreateNodes(numberOfNodes,
+
+			incubator, ok := blockchain.(container.NodeIncubator)
+			Expect(ok).To(BeTrue())
+
+			nodes, err = incubator.CreateNodes(numberOfNodes,
 				container.ImageRepository("quay.io/amis/geth"),
 				container.ImageTag("istanbul_develop"),
 				container.DataDir("/data"),
diff --git a/tests/quorum/functional/block_sync_test.go b/tests/quorum/functional/block_sync_test.go
index bf714e19..b11376fc 100644
--- a/tests/quorum/functional/block_sync_test.go
+++ b/tests/quorum/functional/block_sync_test.go
@@ -57,7 +57,11 @@ var _ = Describe("Block synchronization testing", func() {
 
 		BeforeEach(func() {
 			var err error
-			nodes, err = blockchain.CreateNodes(numberOfNodes,
+
+			incubator, ok := blockchain.(container.NodeIncubator)
+			Expect(ok).To(BeTrue())
+
+			nodes, err = incubator.CreateNodes(numberOfNodes,
 				container.ImageRepository("quay.io/amis/geth"),
 				container.ImageTag("istanbul_develop"),
 				container.DataDir("/data"),